1881636 - [Gecko iOS] Use BrowserEngineKit to start content processes

Status: RESOLVED FIXED

(Firefox for iOS :: General, enhancement)

Description

[Nika Layzell [:nika] (ni? for response)]

Apple has released new APIs to allow building alternative browser engines for iOS in the EU. This patch is to track an initial prototype implementation of launching child processes in Gecko-iOS's ExampleBrowser using these new BrowserEngineKit APIs.

Documentation: https://developer.apple.com/documentation/browserenginekit

Comment 1

[Nika Layzell [:nika] (ni? for response)]

Attachment: Bug 1881636 - Part 1: Add DarwinObjectPtr,

This is a helper smart pointer type for working with Darwin OS data structures.
The code has been directly adapted from WebKit's OSObjectPtr type. This will be
used on iOS to manage the lifecycles of xpc objects.

Comment 2

[Nika Layzell [:nika] (ni? for response)]

Attachment: Bug 1881636 - Part 2: Shim out IOSPlatformFontList to allow it to work in content processes, r=jfkthame!

The existing behaviour attempted to access UIKit from within a content process,
which would not work correctly. After some testing, it turned out the existing
code also always returned a null string, so it's been hard-coded to a temporary value.

Depends on D202522

Comment 3

[Nika Layzell [:nika] (ni? for response)]

Attachment: Bug 1881636 - Part 3: Make URL input in ExampleBrowser more lenient, r=lmarceau!

This new logic is based on the regex from android-components, and allows
entering internal URLs like about:about into the URL bar, which can be useful
when testing.

Depends on D202523

Comment 4

[Nika Layzell [:nika] (ni? for response)]

Attachment: Bug 1881636 - Part 3: Implement IosProcessLauncher::DoLaunch.

These changes switch Gecko-iOS to using BrowserEngineKit's ExtensionKit-based
processes to start content processes on iOS. These processes are started with
an initial xpc connection, which is then used to communicate a command line,
initial file descriptors and environment variables before invoking
content_process_main.

The XPC connection is not used further after the bootstrap message, which seems
to roughly match how WebKit uses these APIs.

3 separate extensions have been added for Networking, Rendering and WebContent,
as is required by iOS. Currently these appear to fully duplicate XUL and its
resources between each extension, despite the code being all bundled into a
shared framework.

Depends on D202524

Comment 6

[Mike Hommey [:glandium]]

Attachment: Bug 1881636 - Part 2 - Expose SetClientChannelFd, SetPrefsFd and SetPrefMapFd on iOS.

Comment 7

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/a8260a45c5c9
Part 1: Add DarwinObjectPtr, r=glandium,sylvestre
https://hg.mozilla.org/integration/autoland/rev/71179f624966
Part 2 - Expose SetClientChannelFd, SetPrefsFd and SetPrefMapFd on iOS. r=ipc-reviewers,nika
https://hg.mozilla.org/integration/autoland/rev/5079ead12099
Part 3: Implement IosProcessLauncher::DoLaunch. r=glandium,ipc-reviewers,jld
https://hg.mozilla.org/integration/autoland/rev/babb5943701f
apply code formatting via Lando

Comment 8

[Serban Stanca [:SerbanS]]

https://hg.mozilla.org/mozilla-central/rev/a8260a45c5c9
https://hg.mozilla.org/mozilla-central/rev/71179f624966
https://hg.mozilla.org/mozilla-central/rev/5079ead12099
https://hg.mozilla.org/mozilla-central/rev/babb5943701f